Small Thermoelectric Generators （小型热电发电机）.pdfVIP

Small Thermoelectric Generators by G. Jeffrey Snyder hermoelectric generators are all solid-state devices that convert Theat into electricity. Unlike traditional dynamic heat engines, thermoelectric generators contain no moving parts and are completely silent. Such generators have been used reliably for over 30 years of maintenance-free operation in deep space probes such as the Voyager missions of NASA.1 Compared to large, traditional heat engines, thermoelectric generators have lower efficiency. But for small applications, thermoelectrics can become competitive because they are compact, simple (inexpensive) and scaleable. Thermoelectric systems can be easily designed to operate with small heat sources and small temperature differences. Such small generators could be mass produced for use in automotive waste heat recovery or home co-generation of heat and electricity. Thermoelectrics have even been miniaturized to harvest body heat for powering a wristwatch. Thermoelectric Power A thermoelectric produces electrical power from heat flow across a 2 temperature gradient. As the heat flows from hot to cold, free charge carriers (electrons or holes) in the material are also driven to the cold end (Fig. 1). The resulting voltage (V) is proportional to the temperature difference (∆T) via the Seebeck coefficient, α, (V = α∆T). By connecting an electron conducting (n-type) and hole conducting (p-type) material in series, a net voltage is produced that can be